The present invention relates to a method for manufacturing a drape for use in endoscopic surgery and to a drape for use in endoscopic surgery.
Endoscopic surgery is a low-invasive surgical technique. Also known as keyhole surgery, endoscopic surgical procedures require that only small incisions be made in the skin, which minimises damages to muscle, skin and tissue. In endoscopic surgical procedures, thin, elongate medical instruments are passed through one or more incisions in the skin. In order to provide the surgeon with a view of the site of the operation (the actual site of the operation is covered by the skin), it is usual to use an endoscopic telescope to supply pictures to a camera and from there to a visual display unit, such as a television screen. The endoscopic telescope is easily sterilised by autoclaving and this is necessary because the telescope has one end thereof inserted through an incision in the patient during the operation. The other end of the telescope is optically linked to the camera and the camera sends pictures of the operating site to the visual display unit. Unfortunately, the camera is normally not able to be sterilised by autoclaving because autoclaving would damage the optical components of the camera.
The camera is optically linked to the telescope and this may represent a potential breach of the sterile field. To avoid potential difficulties with breach of the sterile field, it has become common practice to cover the unsterile camera and its associated cable with a sterile cover.
One such sterile cover is disclosed in U.S. Pat. No. 4,914,521 in the name of Adair. This patent discloses an apparatus for enclosing a non-sterile camera and its trailing cable. The apparatus includes a sterile cylindrical housing for receiving a camera at one end and a flared annular mounting for receiving an optical transmitting means, such as an endoscopic and associated xe2x80x9cCxe2x80x9d mount at its other end. The housing includes a clear window that is located between the endoscope and the lens of the camera and that allows light to pass from the endoscope to the camera. The clear lens also acts as a bacteria barrier between the camera and the endoscope. A plastic sleeve is attached to the outer part of the housing by adhesive tape. In use, the sleeve (which is sterile) is pulled back over the camera cable to maintain sterility about the camera cable.
International Patent Application No. PCT/US95/14735 (publication No. WO 96/17558) also in the name of Adair discloses a surgical drape that allows greater flexibility in use than that described in U.S. Pat. No. 4,914,521. Again, the drape includes a housing having a sterile sleeve positioned over a neck portion of the housing such that a fluid and air tight seal is formed. Typically, the seal between the sleeve and the housing is formed by surgical tape, adhesives, shrink wrapping or use of double-faced adhesive strips.
A potential difficulty with the apparatus described in U.S. Pat. No. 4,914,521 and WO 96/17558 resides in the use of adhesives or similar means to join the sleeve to the housing. In practice, it can prove to be difficult to obtain a leak-proof seal that will be effective in maintaining sterility.
The present invention provides a method and an apparatus that overcomes or at least ameliorates the above-mentioned disadvantage of the prior art.
In a first aspect, the present invention provides a method for manufacturing a drape for use in endoscopic surgical procedures, the method including the steps of positioning a portion of a sheath of flexible material adjacent to or in abutment with a joining portion of a first housing piece, positioning a joining portion of a second housing piece adjacent to or in abutment with the portion of the sheath and the joining portion of the first housing piece and joining the joining portions of the first housing piece and the second housing piece to thereby form a housing and entrap the portion of the sheath between the first housing piece and the second housing piece.
The portion of the sheath is preferably an end of the sheath. Preferably, an edge of the portion of the sheath is entrapped between the first housing piece and the second housing piece.
Preferably the sheath of flexible material is generally cylindrical in shape. The distal end of the sheath is fitted between the two housing pieces with an edge of the distal end overlapping part of the joining portions of the two housing pieces. Subsequent joining of the two housing pieces to form the housing also entraps, or crimps, the end of the sheath between the two housing pieces and this ensures that a leak-proof seal is formed between the housing and the sheath. It is not necessary to use tape or adhesive to join the end of the sheath to the outer wall of the housing. Rather, the end of the sheath is trapped or crimped within the housing.
The housing pieces may suitably be made from plastics material. A suitable material may be general purpose polystyrene mixed with a blend of K-resin. This material is gamma-ray stable and can be transparent. Another suitable material may be an ABS mixture or blend, which lends itself to ultrasonic welding.
The housing may include a camera coupling for coupling a camera thereto. The sheath is then pulled along the cable extending from the cable to cover the non-sterile cable with the sterile sheath.
The housing may also include a telescope coupling for coupling an endoscopic telescope thereto. Throughout this specification, the term xe2x80x9ctelescopexe2x80x9d is considered to include any device used in endoscopic surgery to transmit an optical signal to the camera.
Most preferably, the housing includes a camera coupling and a telescope coupling. In this embodiment, the drape provides a convenient means for optically linking the telescope to the camera whilst maintaining sterility in the sterile field. It is preferred that one of the first or second housing pieces includes the camera coupling and that the other of the first or second housing pieces includes the telescope coupling. In this arrangement, the housing can be assembled by joining two pieces. However, it will be appreciated that the camera coupling and/or the telescope coupling could comprise separate pieces that can be connected or joined to the first and/or second housing pieces. In such cases, the complete housing comprises the first and second housing pieces joined together and the camera coupling and/or telescope coupling connected thereto.
The housing preferably includes an optically clear pathway between the telescope coupling and the camera coupling to allow good quality pictures of the operating site to be transmitted to the visual display unit. The optically clear pathway may be provided by producing the housing from transparent material. Alternatively, a clear window or lens may be included within the housing.
If a clear window or lens is used, the window or lens is preferably located between the position of the camera (in use) and the telescope so that the window acts as a barrier. Indeed, it will be appreciated that the housing should include a barrier between the camera and the telescope to maintain sterility and to exclude the non-sterile camera from the sterile field.
The joining portion of the first housing piece preferably comprises a joining face. Similarly, the joining portion of the second housing piece preferably comprises a joining face. To join the housing pieces together, the joining faces are placed closely adjacent to or in abutment with each other (with the edge of the end of the sheath therebetween) and the joining faces are joined together at at least a portion of their faces.
In embodiments where the first and second housing pieces are made from plastics material, the first and second housing pieces are preferably joined by ultrasonic welding. The joining portion of one of the first or second housing pieces may include an energy director to enhance the ultrasonic weld. The energy director may comprise a raised ridge extending around the joining portion and preferably being located towards the centre of the joining portion.
As mentioned above, the end of the sheath is trapped between the first and second housing pieces when they are joined together to form a leak-proof seal. The seal between the sheath and the housing may be improved by positioning a thermoplastic material between the end of the sheath and one of the joining portions. The thermoplastic material is a material that can melt and adhere to the material of the sheath. Once the end of the sheath has been placed over the joining portion, the sheath material may be impulse sealed to the joining portion via the thermoplastic material. The thermoplastic material is preferably a thermoplastic rubber (TPR). The thermoplastic material may be in the shape of a gasket or an xe2x80x9cOxe2x80x9d-ring. To assist in positioning the gasket or O-ring, a groove may be formed on the associated joining portion and the gasket or O-ring placed in the groove. It is believed that use of a thermoplastic material, such as a TPR gasket or O-ring, will assist in improving the seal formed between the sheath and the housing. Indeed, it is believed that use of the thermoplastic material should result in the formation of a water-tight, leak proof seal which will thus form a sterility barrier. However, it will be appreciated that a leak proof seal between the sheath and the housing may be obtained without use of the thermoplastic material.
In another embodiment, the method of the present invention includes the steps of providing a thermoplastic material on the first housing piece, positioning the portion of the sheath over the thermoplastic material and adjacent to or in abutment with the joining portion of the first housing piece, joining the sheath to the thermoplastic material, and subsequently joining the first and second housing pieces.
In a preferred form of this embodiment, the invention further includes the steps of placing a lens in the first housing piece prior to joining the first and second housing pieces. Alternatively, the lens may be placed in the second housing piece prior to joining the first and second housing pieces. The lens may be placed in the first housing piece either before or after the thermoplastic material and sheath are joined. The step of joining the first and second housing pieces may act to affix the lens in the housing, for example, by ultrasonic welding. Alternatively, the lens may be affixed to either of the first housing piece or second housing piece prior to joining the first and second housing pieces.
The thermoplastic material may be joined to the sheath by welding, such as impulse welding. The thermoplastic material preferably comprises a gasket. The gasket may be placed in a groove formed in the first housing piece.
In some instances, the sheath may extend across the optical pathway in the housing. If the sheath is made from a material that will affect optical clarity or quality, the sheath material is preferably removed from the optical pathway prior to joining the first and second housing pieces together or after joining the first and second housing pieces together.
The camera coupling and telescope coupling of a preferred embodiment of the present invention may be any suitable couplings known to the skilled person. The camera coupling is preferably a xe2x80x9cCxe2x80x9d coupling that is widely used in endoscopic procedures and need not be discussed farther.
The sheath is preferably made from thin film plastics material. Polyethylene is a suitable material for the sheath. The sheath is preferably transparent. The sheath may be rolled up or folded in a telescopic or accordion-like manner to facilitate positioning of the sheath over the camera cable. The proximal end of the sheath may be fitted with a pull-tab to simplify positioning of the sheath. One or more resealable adhesive tabs may be placed on the sheath to enable the sheath to be closely conformed to the cable.
In some embodiments of the present invention the material of the sheath may not readily join to the material of the housing pieces. In such cases, it is preferred that the sheath is positioned between the housing pieces such that the sheath does not fully cover or extend fully between the joining portions of the housing pieces. This allows at least a part of one joining portion to be in contact with at least a part of the other joining portion. The joining procedure then joins the parts of the joining portions in contact with each other.
To improve the seal between the end of the sheath and the housing, the joining portions of the first and second housing pieces may have a degree of surface roughness, surface serrations, or the like, to improve mechanical contact between the sheath and the housing. When the housing pieces are joined to form the housing, the first and second housing pieces are located very close to each other and thus sandwich the end of the sheath between them. The surface roughness, surface serrations or the like assist in holding the sheath in the housing. Moreover, if ultrasonic welding is used to join the two housing pieces, molten plastic from the housing pieces may flow around the edge of the end of the sheath to further hold the sheath.
The present invention also encompasses a drape. In accordance with a second aspect, the present invention provides a drape for use in an endoscopic surgical procedure, the drape including a housing comprising a first housing piece joined to a second housing piece and a sheath of flexible material having a portion thereof connected to the housing, wherein the sheath is connected to the housing by positioning a portion of the sheath between the first housing piece and the second housing piece prior to joining the first and second housing pieces and wherein the portion of the sheath is trapped between the joined first and second housing pieces to thereby establish a leak-proof seal between the sheath and the housing.
Preferably, the portion of the sheath is an end of the sheath. Preferably, the portion of the sheath is joined to one of the first or second housing pieces by joining the sheath to a thermoplastic material positioned on the one of the first or second housing pieces prior to joining the first and second housing pieces.
The housing preferably further comprises a camera coupling for coupling a camera thereto and a telescope coupling for coupling a telescope thereto, the housing effective to establish an optical link between the telescope and the camera. The housing should provide an optically clear pathway between the telescope and the lens of the camera. The housing should also include a barrier between the camera and the telescope to preserve sterility in the sterile field. The combination of the sterile barrier within the housing and the sterile sheath that may be draped over the camera and its associated cord ensures that the non-sterile camera does not compromise the sterile field.
The telescope coupling may comprise a xe2x80x9cCxe2x80x9d-coupling that is well known to skilled persons. Any other suitable coupling may also be used as the telescope coupling. Similarly, the camera coupling may comprise any suitable coupling known to the skilled person. The telescope coupling and/or camera coupling may be formed integrally with the first and second housing pieces, or they may comprise additional pieces to be connected to the housing.
In a third aspect, the present invention provides a drape for use in an endoscopic surgical procedure, the drape including a housing including a first housing piece having a joining portion joined to a joining portion of a second housing piece, a sheath of flexible material having a portion positioned between the first and second housing pieces, a thermoplastic material positioned between the portion of the sheath and one of the first and second housing pieces, the thermoplastic material affixing the portion of the sheath to the one of the first and second housing pieces and wherein the joining portions of the first and second housing pieces surround and entrap an edge of the portion of the sheath in the completed housing.
The housing of the drape of the second and third aspects of the invention preferably includes a lens positioned between the first and second housing pieces.
In another aspect the present invention provides a drape for use in an endoscopic surgical procedure comprising a housing and a sheath of flexible material joined to the housing to form an essentially leak-proof seal between the sheath and the housing, the housing having a camera coupling means for coupling a camera thereto and a telescope coupling means for coupling an endoscopic telescope thereto, the housing having an optical pathway therein to enable light and/or an image from the endoscopic telescope to be transmitted to the camera, wherein a corrective lens is placed in the optical pathway.
The housing of the drape acts as an adaptor for connecting the camera and the telescope. Instead of the camera and telescope being directly connected to each other, the housing is positioned between the camera and the telescope with the camera and the telescope each connected to the housing. This acts to interpose a member between the camera and the telescope which results in the respective ends of the camera and telescope being separated somewhat during the oration. This may result in the image from the telescope not being properly focussed on the camera, which can result in the image from the camera that is displayed on the visual display unit during the operation being out of focus. The corrective lens incorporated into the housing overcomes this problem. As a further advantage, the corrective lens also acts to enhance or maintain the size of the picture on the visual display unit.
The corrective lens preferably has a corrective power sufficient to produce an in-focus picture on the visual display unit during the operative procedure. A lens with a power of from 1 to 10 dioptive is preferred, more preferably about 2.0 dioptive.
The drape of the present invention is preferably made in accordance with the first aspect of the present invention, as described hereinabove. In this method, the housing is made from first and second housing pieces joined together, with the sheath entrapped between the first and second housing pieces.
The lens preferably is an anti-fog lens or has an anti-fog coating applied thereto in order to minimise fogging during use. For example, the lens may be made from an anti-fog material or it may be sprayed or coated with an anti-fog material.
The telescope coupling means may be any conventional coupling means known by the person of skill in the art to be suitable. A conventional xe2x80x9cCxe2x80x9d coupling is one example. Similarly, the camera coupling means may be any convention coupling means known to be suitable to a person of skill in the art.
The sheath is preferably made from thin film plastics material. Polyethylene is a suitable material for the sheath. The sheath is preferably transparent. The sheath may be rolled up or folded in a telescopic or accordion-like manner to facilitate positioning of the sheath over the camera cable. The proximal end of the sheath may be fitted with a pull-tab to simplify positioning of the sheath. One or more resealable adhesive tabs may be placed on the sheath to enable the sheath to be closely conformed to the cable.
In yet another aspect, the present invention provides la drape having a housing in which the telescope coupling means can allow at least a degree of rotation of the telescope or substantially prevent rotation of the telescope.
In this aspect the present invention provides a drape for use in an endoscopic surgical procedure comprising a housing and a sheath of flexible material joined to the housing to form an essentially leak-proof seal between the sheath and the housing, the housing having a camera coupling means for coupling a camera thereto and a telescope coupling means for coupling an endoscopic telescope thereto, the housing having an optical pathway therein to allow light and/or an image from the telescope to be transmitted to the camera, wherein the telescope coupling means includes locking means operative between a first position wherein the telescope is connected to the telescope coupling means and can rotate within the telescope coupling means and a second position where the telescope is connected to the telescope coupling means and locked against rotation within the telescope coupling means.
The drape of the present invention preferably includes the corrective lens of the one aspect of the invention and the locking means of another aspect of the invention.